A WARM spring morning, and the atmosphere is more rock concert than revolution. Chicken kebabs are sizzling on pavement stalls. Giggling teenage girls in skinny jeans are dancing to a rap number on the back of a open-back truck. They and their high-school classmates have skipped school to go on a manif, or demo, in protest at the French Socialist government’s liberalising labour bill. “It is festive,” agrees Florian Mazet, a final-year lycée pupil, over the pounding beat from the truck’s amplifier: “We don’t want to be confrontational, but if we have to, we are ready for it.”

April 5th was the fourth of a series of one-day protests in which high-school pupils and university students joined unionists on the streets. This time some 34 lycées were shut, mostly due to blockades by pupils. The turnout was down on the previous week, but violence was up. After clashes with troublemakers in Paris, the police set off tear gas and detained 148 people. French students are campaigning not against harder exams or higher university fees, but against a draft law that would ease the negotiation of longer working hours and limit payouts for unfair dismissals. “Insecure youth is angry!” read one home-made placard.

The heart of the complaint is that a Socialist government, meant to be the guardian of workers’ rights, is pandering to corporate bosses by dismantling them. Worse, goes the charge, it is making the disingenuous claim that this will help employers create jobs. “Who could possibly believe that making redundancies easier will create jobs?” reads a union flyer handed out at the rally. “Thomas Piketty agrees,” says one student triumphantly, referring to an article in Le Monde, a newspaper, in which the best-selling French economist argued that reducing redundancy costs will not curb unemployment.

Yet Mr Piketty was not the only rock-star French economist to opine on the labour reforms. In his own piece in Le Monde, Jean Tirole, a Nobel prize-winner, argued the opposite: that the insecurity of the young is precisely the fault of over-protected “insider” jobs. Because businesses fear being burdened with such employees, 90% of new hires are now for temporary jobs, and young people can be stuck with short-term contracts for years. The new labour law, argued Mr Tirole, should lead to more permanent hires and curb youth insecurity.

François Hollande, who campaigned to put youth at the centre of his presidency, has simply failed to make this case convincingly. He is already enfeebled, having been forced by a political outcry to shelve a proposal to strip nationality from French-born dual citizens convicted of terrorism. Now, protests against the labour bill have prompted the government to water down some provisions. Manuel Valls, the prime minister, has met with student leaders to hear their complaints.

Only about 8.5% of France’s 2.4m students take part in elections to university union bodies, and the National Union of French Students (UNEF), the country’s biggest, has just 19,000 members. Yet their capacity to frame national debates and influence policy far exceeds this strength. One reason is that when la jeunesse gets involved in protests, the authorities get nervous. High-school pupils, who in France have their own unions, are particularly unpredictable. The revolutionary imagery of 1968 (though rarely its existentialist wit) still informs today’s chants and slogans. Protests can rapidly become violent, especially in the face of high-handed policing.

Do you hear the people sing

Equally important, student unions are an incubator of the next generation of political leaders. Many Socialist politicians began their careers at UNEF, including both Mr Valls and Mr Hollande. Jean-Christophe Cambadélis, the current Socialist Party head, was a UNEF leader. And universities seem remarkably tolerant of student politics intruding on studies. Today’s UNEF leader, William Martinet, is 27 years old and graduated only last year.

“It’s a great training school,” says Bruno Julliard, who led UNEF a decade ago and is now one of Paris’s 21 deputy mayors. Ten years ago, he made his name by leading a massive student protest against a previous liberalising labour bill. The centre-right government at the time was forced to back down, and folk memories of that struggle linger. Student protests are a “sign of democratic vitality”, says Mr Julliard: “The French like their rebellious side, so they are looked upon kindly. Through young people, we express the ideals of the country.” Mr Hollande’s failure today is an inability to explain how, even with liberal policies, such ideals can still be upheld.